1. Field of the Invention
This invention relates to tractor tool attachments for grasping and moving objects.
2. Description of Related Art
Currently, the most common way to lift heavy objects in the field requires the use of a rubber-tire tractor, front loader, a bucket with hooks welded to it, and a chain. The tractor operator manipulates the tractor arms to position the bucket over or under the object to be moved. Then a tractor foot pedal is set, the operator steps off the tractor, wraps the chain around the object, secures it to the hooks on the bucket, returns to the tractor and slowly and carefully lifts and then moves the object to the desired new location. One problem with this method is that the chain frequently slips and must be adjusted, a time-consuming task. The object may shift suddenly, striking the tractor. Another problem is that many objects cannot be secured with a chain at all. If the object is heavy, a bucket hook may give way resulting in a sudden drop in the load, which may damage the tractor or, worse, injure the operator. In addition, the operator must rely heavily on the tractor brake system for safety when securing the load. Once the object has been placed at the desired location, the operator must set the brake, get off the tractor, and unwrap the chain from the object and bucket hooks. This process is repeated for each object moved. It is a time-consuming, labor-intensive process. An alternative is to have ground personnel assist the tractor operator, but this is both an additional expense and the ground person could be injured if the chain or load suddenly shifted.
Some special devices have been made in an attempt to alleviate these problems. John Clatterbuck describes a "Front End Attachment for Tractors" in U.S. Pat. No. 3,140,786. Clatterbuck's attachment comprises a pair of jaw members that rely on a fork lift attachment. The jaw members are attached over the forks which guide the motion of jaws as they open and close. There are several disadvantages to Clatterbuck's tractor attachment. It is complex and cumbersome to install and remove from a tractor. Additionally, Clatterbuck's jaw design relies on forks which obstruct certain desirable operations. The forks are used to provide strength and to align the opening and closing movement of the jaws; these jaws will not operate unless they are attached to forks. Because Clatterback's jaws rely on the forks positioned in the most closed position the forks prevent many types of objects from being deposited on a surface below the jaws. For example a tree having a canopy wider than the fork spacing will not drop through the forks. The size of object that will freely drop through the forks, as one might desire if loading debris into a debris bin or truck, is limited to the space between the so forks. It should be noted in this regard that Clatterbuck teaches using the forks in the most closed position in order to provide mechanical support for his jaw members. Furthermore, the forks are positioned with only a narrow separation, and this restricts the ability to grasp and move bulkish, large, awkward objects. Additionally, the forks extend well beyond the jaw members. As a result, the forks interfere with a variety of desirable functions such as tilting the jaws toward the ground to grab an object near the ground or to use the tilted jaw to provide added leverage in pulling an item out the ground after grabbing it.
James W. Riddle describes a tractor attachment for removing fallen trees in his U.S. Pat. No. 4,993,914. Riddle's attachment is designed to attach to the back of a tractor. The tractor is backed up to a root system of an already uprooted tree and is then used to lift the roots a short distance off the ground, vertically, so that the tree which is lying on the ground can be dragged along behind the tractor. Riddle's attachment is not useful for uprooting trees or bushes. The Riddle attachment lacks utility for a number of other desirable tasks such as moving or removing fence posts from the ground, moving rocks, or lifting and moving any number of oddly shaped man-made items. Furthermore, the jaws of Riddle's tool cannot be tilted; they lift only in a vertical direction. As its title suggests, the Riddle implement performs only a single task. It is not a universal tool; it is a "Fallen Tree Removal Implement".
In U.S. Pat. No. 5,584,646, Billy M. Lewis, et al. disclose a complex "Handling Apparatus" that can be mounted to a turret positioned on top of a vehicle cab. Objects are gripped for moving from one place to another using gripping chains that are connected to chain tensioners. The Lewis, et al. structure is made for shop use and thus emphasizes a small footprint that may not be stable in the field. In addition, it is extremely complex and difficult to build and disassemble. It appears to be designed for use on a dedicated vehicle.
It would be very desirable to have a tractor tool that could be attached to and detached from the tractor easily with only a few fastening points and that was capable of a large number of varied grasping and moving tasks such as lifting heavy objects or uprooting trees or pulling posts out of the ground and repositioning the object in a easy, precise, and flexible manner.